Conventionally, monitors capable of providing, with the use of an exclusive-use device such as stereoscopic glasses, a stereoscopic view of two-eye disparity images taken from two viewpoints have been in practical use. Further, in recent years, monitors capable of providing, with the use of a light beam controller such as a lenticular lens, a glass-free stereoscopic view of multiple-eye disparity images (e.g., nine-eye disparity images) taken from a plurality of viewpoints have also been in practical use. The two-eye disparity images and the nine-eye disparity images displayed on the monitors capable of providing a stereoscopic view may be generated, in some situations, by estimating depth information of an image taken from one viewpoint and performing image processing while using the estimated information.
Incidentally, as for medical image diagnosis apparatuses such as X-ray Computed Tomography (CT) apparatuses, Magnetic Resonance Imaging (MRI) apparatuses, and ultrasound diagnosis apparatuses, such apparatuses have been in practical use that are capable of generating three-dimensional medical image data (hereinafter, “volume data”). Conventionally, the volume data generated by such a medical image diagnosis apparatus is processed into a two-dimensional image as a result of various types of image processing and is displayed two-dimensionally on a general-purpose monitor. For example, the volume data generated by the medical image diagnosis apparatus is processed into a two-dimensional image that reflects three-dimensional information as a result of a volume rendering process and is displayed two-dimensionally on a general-purpose monitor. According to the conventional technique, however, when a plurality of images corresponding to mutually-different time phases is superimposed together, there are some situations where it is difficult to view the images.